Thousands of years ago, where St. Petersburg now stands, there was a sea, known in modern times as the Littorina Sea, named after the gastropods, Littorina, that lived in the Baltic waters. From the shells of ancient mollusks settling on the bottom of the water bodies, granite gradually formed, which over the centuries clothed the Neva River in its red-black attire. This film tells the story of how a fairytale city grew from water and stone.